Questions about the fuel delivery - B18FT

[TommiS]

Question 1: What is the job of this thing ? http://tommis.galleria.fi/kuvat/Random/valvething.jpg
Question 2: Is it normal that when i open that fuel line after about 20 hours from running last time there is no pressure at all left in the line.

The thing is that i have pretty good cold start after decent amount of starting but when engine is half temp it struggles in start. And iam thinking that the fuel is already halfway in tank ? Warm start is working very good.

What do you guys think about this ?

[Iroll480]

The bad starting with half warm engine sounds to me as a bad cold start sensor. It's located under the most right sparkplug with a brown connector. If the coolant is 80c the resistance of the coldstarsensor should be 330ohm, at 20c 2500ohm and at 0c it should give 5800ohm.
The small UFO thingy is the pressure damper or whatever the right English term maybe. And it's perfectly normal that after 20hours there's no pressure left in the system. That's why you first set the ignition key on, wait till the petrolpump stops running and then turn the key to start. This is to built up pressure in the petrol circuit again. You can hear the pump from between the rearseats.

[TommiS]

The bad starting with half warm engine sounds to me as a bad cold start sensor. It's located under the most right sparkplug with a brown connector. If the coolant is 80c the resistance of the coldstarsensor should be 330ohm, at 20c 2500ohm and at 0c it should give 5800ohm.
The small UFO thingy is the pressure damper or whatever the right English term maybe. And it's perfectly normal that after 20hours there's no pressure left in the system. That's why you first set the ignition key on, wait till the petrolpump stops running and then turn the key to start. This is to built up pressure in the petrol circuit again. You can hear the pump from between the rearseats.

Temp sensor is new, original Bosch. First thing that i changed. That "Ufo" thing really messes my mind what is the meaning of that ?

And then to the intresting thing. My petrolpump doesnt run when i turn ignition on ? Should it really in turbo ? Petrol starts to flow only when iam starting the car, when motor cranks. I know that some cars build the pressure before start but is it 100% sure that it should do that in turbo ?

[glasgowjim]

all 480 s have an electrical fuel pump. the system should prime/pressurise for a couple of seconds before ignition.

ufo thing is a fuel pressure regulator.

[TommiS]

all 480 s have an electrical fuel pump. the system should prime/pressurise for a couple of seconds before ignition.

ufo thing is a fuel pressure regulator.

So, there should be relay that is ON for couple of seconds or is it controlled by ECU ?

I'am pretty sure that pressure regulator is in the other end of the engine. That metal thing that connects to injector rail.

[Iroll480]

It's not the pressure reg. The pr has 3 connection and is bigger while the ufo only one in and 1 out connection. It's there to dampen sudden pressure peaks or drops iirc.
Yes there is a relay that controls the priming. It's under the dash somewhere above your left leg in a rhd. The're two relais one fuel and one main next to each other. Can't remember which is wich though.

[bbf]

'90 turbo has no priming. it has to crank a couple of times, than it starts pumping and igniting.. it starts at once only at jumpstart.

[glasgowjim]

Well you learn something new every day the oldest 480 I have driven/owned or broken was a J reg so the older cars were completely different.

[TommiS]

'90 turbo has no priming. it has to crank a couple of times, than it starts pumping and igniting.. it starts at once only at jumpstart.

This is basicly what i wanted to hear So i think the problem might be something else than fuel delivery.

Car idles perfect and runs good but this starting problem is driving me nuts !

[Robou]

Knowing what actually happens at starting the engine may help to solve the problem:

Under ±45 revs/min the fuel pump is not activated. (This is a safety precaution).
Until 600 revs/min two injections per rev. occur, the duration of which depend on
*engine temperature
*engine speed
*number of completed revs.
*time passed
Once 600 revs/min are reached, the program switches back to 1 injection per rev.
It now monitors time, temperature and engine speed in order to decide the injection time.
Once the temperature is in the range of normal operation the "normal" program starts and the MAF gets involved.

This all has to do with the LH2.2 ECU.

Considering the symptoms and the above I would say the temperature sensor readout is at fault. As a matter of fact, all of the other parameters can be ruled out, the car running fine.

To be sure and rule out wiring defects you should check at the ECU. Pin 2 is connected to the sensor.
Between pin 2 and pin 25(ground) ≥2Volts should be present at ≤20ºC, ≤0.35Volts at ≥80ºC with ignition switched on. 5Volts indicate a wiring and/or sensor defect.
Less complicated, measure, ingition switched off, connector disconnected, the resistance between pin 2 and 25 at the connector. This should be ≥2500Ω at ≤20ºC and ≤330Ω at ≥80ºC.
Another trick is to fool the ECU by connecting dummy resistors in stead of the sensor and see what happens. But I strongly recommend measurement at the ECU, this will reveal any faulty condition.

[TommiS]

Thank you very much for that info Robou

I will measure the temp sensor tomorrow from the ECU.

But the info that i got now got me qurious

1. Is there only one temp sensor for the ECU ? (the one near the sparkplug in the gearbox side)
2. Is it possible that idle valve is broken or faulty adjusted that it wont allow car to start properly
3. Is there any more info about the MAF involving to the start ? When does that happen ?
4. Is there any ohm. readings to the engine speed sensor ? I cleaned it another day but i didnt help anyway.
5. What about lambda, does it have any meaning in starting ?

[Robou]

1- There's a lot of temperature sensors but the ECU uses to this purpose the one in front of the engine.
2- If idling is OK the valve won't be broken. It hardly ever is, although it is often blamed.
3- With the MAF disconnected the engine will start. Runs lousy, though.
4- There is, it should be between 280Ω and 160Ω. Measured at the connector of the EZ210K in order to rule out wiring problems.
5- Strangely, the lambda sensor is taken into account. If your car is older than around '93 you can disconnect it. The result is a slightly richer mixture.

[bbf]

Turbo has 2 temp senzors in one. under spark plug 1 and 2 (red connector) is a double temp senzor, thous 2 wires. each is referenced to earth. one drives turbe/ignition ecu (EZ210), other drives LH2.2 injection ecu. they are the same and must have the same resistance (+-20% is OK).

[TommiS]

I have been doing loads of different tests with the car. Temp sensor seems to be OK. i got readings close to the haynes and what you guys have said. Also flywheel sensor gave good readings.

BUT i may have give information that is not correct. The thing is, it doesnt matter is it warm or cold but when it is the second start from the cold engine it stalls. AArrrgh this is really hard to explain when using english

This morning: +9 at the inside garage and cars starts beatifully and idles perfect. I turn off the engine after about 30 seconds of running and start again after about few minutes = engine stalls before takes any revs, i start again...little sturggling but starts and also idles after little struggling.

Almost same thing happens when engine is warm +85c. When i turn engine off warm and start again in 2 minutes it will usually starts good but if i wait 10-15 minutes the struggling is there. Sometimes it survives the struggle at first start and sometimes it need a second start.

I really dont know what to check anymore, i have allready double checked loads of stuff.

Any ideas ? Or should i just drive the damn thing to frozen lake and wait for summer

[glasgowjim]

I vote for the lake

[Iroll480]

Maybe leaking injector(s)? Check the sparkplugs to see if they are black and/or wet when it doesn't want to start.

[Robou]

This is quite different from what you told in your first post.
Sounds indeed like a flooded engine.

[bbf]

i had this strange phenomena with my turbo: sometimes it didn't want to start, it strated turning and stoped at certain point, ie a piston stalled ?! it took all the voltage and ofcourse i gave up cranking. after 10 seconds i tried again, it went (not so softly) over that stall and engine started , but runing on 2 or 3 cilinders - for 10 minutes or so. This simptom was gone along with my 100€ for the injector cleaning! one injector must have flooded overnight and not only once.

[TommiS]

Yea, i know that i misinformed you guys at the first post.

Injectors then...well i have another set of the standard injectors from turbo so i could try them. I did little injector work some time ago. I changed all the O-rings and tested the injectors with battery and injector cleaner. But obviously i cannot know if they leak mechanically.

Thanks for the help, i let you know what happens

[TommiS]

New (used) injectors fitted with new O-rings...Nothing changed....

Well...iam out of ideas. Have to change to carburetor cars now, they never fail like this.